Medium attaching device and disk drive apparatus

ABSTRACT

There is disclosed a medium attaching device and a disk drive apparatus which are suited for a compact and lightweight design and a thin design, and are capable of automatic attachment of a disk. The device includes a rotary support device for holding a disk medium thereon, and a rotation drive device for rotating the rotary support means so as to rotate the disk medium. The rotation drive device includes a reciprocally-moving device for reciprocal movement in a direction of an axis of a rotation shaft. The rotary support device has a plurality of pivotal attaching devices pivotally mounted thereon, and each of the pivotal attaching devices is pivotally movable between a fixed position where the pivotal attaching device fixedly holds the disk medium and a received position where the pivotal attaching device is received in the rotary support device. The plurality of pivotal attaching devices are provided on the rotary support device in concentric relation to the axis of the rotation shaft. The pivotal attaching devices are engaged with the reciprocally-moving device, and are pivotally moved by the reciprocal movement of the reciprocally-moving device, thereby fixing and releasing the disk medium relative to the rotary support device.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a disk drive apparatus for driving orrotating a disk medium, and more particularly to a disk medium attachingdevice capable of releasably attaching a disk thereto.

[0003] More specifically, this invention relates to a medium attachingdevice for holding and releasing a concentric disk medium on aturntable, connected to a motor (rotating device for rotating thisturntable), when this disk-like medium is to be driven for rotation.Here, the concentric disk-like mediums (disk media) include, forexample, an old-fashioned EP record disk, an MO, a PD, a CD, a CD-ROM, aCD-R, a CD-RW, a DVD-ROM, a DVD-RAM or the like, and these disk mediumswill be referred to merely as “disk”.

[0004] 2. Description of the Related Art

[0005] Conventional clamp mechanisms for a disk will be described. Therehave heretofore been used three kinds of clamp mechanisms describedbelow. A first example of them is a disk self-holding type (clamp type)as disclosed in JP-A-9-147479, in which the user himself holds or graspsa disk, and attaches the disk directly onto a turntable which is aconstituent part of an optical pickup. This disk holding means is calleda ball chuck-type mechanism which comprises hard balls of metal ormembers of a resin for pressing the disk against the surface of theturntable.

[0006] A second conventional example is a mechanism as disclosed inJP-A-6-84255, in which a disk is transferred to a turntable by a diskloading mechanism, and is placed on a center hub, and then a fixingmember (called a clamper), having a magnetic body, fixes the disk to theturntable from the upper side of the disk by its magnetic force. Fortransferring the disk, there is used, for example, a holder for holdinga cartridge therein or a tray for placing the disk thereon.

[0007] A third conventional example is a method as disclosed inJP-P-61-264547, in which a disk is beforehand contained in a disk casecalled a cassette, and this cassette is inserted into a disk driveapparatus, and a clamp member, provided above the cassette, cooperateswith a magnetic circuit formed by a magnet, provided in a turntable, soas to fix the disk to the turntable.

[0008] In each of these mechanisms, the disk is attached to theturntable or the holder by the operator. Therefore, it has beennecessary to move the turntable or the holder to a position where thisoperation can be effected easily. The disk is attached, and the centerthereof is aligned with that of the rotation drive portion of the diskdrive apparatus, and then the clamp member moves downward to fix thedisk. Therefore, it has been necessary to provide upwardly-moving anddownwardly-moving mechanisms on the opposite (lower and upper) sides ofthe disk, respectively.

[0009] Recently, with the compact and thin design of disk driveapparatus, the disk drive apparatus is, in many cases, contained inportable personal computers. With this trendency, an optical pickup,which is a key device of the disk drive apparatus, has been required tohave a more compact, thinner design. Software, used in computers, hasnow had a large capacity, and in many cases, inexpensive CD-ROMs havebeen used as media to be distributed. Therefore, it is now thoughtnatural that the disk drive apparatus should be mounted on the personalcomputer.

[0010] However, the compact and lightweight design of computers has beenadvanced, and the disk drive apparatus, used as an external memory unitof the computer, has also been required to have a compact, lightweightdesign and a thin design. Therefore, the tray and the upwardly-movingand downwardly-moving mechanisms have been a barrier to the thin design.And besides, in order that a more comfortable operability of thecomputer can be provided, there has been a demand for the type of diskdrive apparatus which does not require the attaching operation by theoperator.

SUMMARY OF THE INVENTION

[0011] With the above problems in view, it is an object of thisinvention to provide a disk drive apparatus suited for a compact andlightweight design and a thin design, and more specifically to provide amedium attaching device and a disk drive apparatus capable of automaticattachment of a disk.

[0012] According to the present invention, there is provided a mediumattaching device comprising rotary support means for holding a recordingmedium thereon, and rotation drive means for rotating the rotary supportmeans so as to rotate the recording medium;

[0013] wherein the rotation drive means includes reciprocally-movingmeans for reciprocal movement in a direction of an axis of a rotationshaft;

[0014] wherein the rotary support means has a plurality of pivotalattaching means pivotally mounted thereon, and each of the pivotalattaching means is pivotally movable between a fixed position where thepivotal attaching means fixedly holds the recording medium and areceived position where the pivotal attaching means is received in therotary support means, and the plurality of pivotal attaching means areprovided on the rotary support means in concentric relation to the axisof the rotation shaft; and

[0015] wherein the pivotal attaching means are engaged with thereciprocally-moving means, and are pivotally moved by the reciprocalmovement of the reciprocally-moving means, thereby fixing and releasingthe recording medium relative to the rotary support means.

[0016] Further, according to the invention, there is a disk driveapparatus using the above medium attaching device.

[0017] The medium attaching device and the disk drive apparatus of thepresent invention are suited for a compact, light weight design and athin design, and is capable of automatic attachment of a disk. In thepresent invention, the rotation drive means and the reciprocally-movingmeans have common parts, and therefore the compact and thin design canbe achieved. Further, in the present invention, even if the disk, whenplaced on the rotary support member, is slightly out of alignment withthe rotary support member and has an error in the thickness of the diskor the diameter of its central hole, this misalignment can be corrected,so that the disk can be positively attached and fixed to the rotarysupport member.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIGS. 1A and 1B are views of a first embodiment of a disk driveapparatus of the present invention, showing a condition before a diskloading operation is effected; FIG. 1A is a schematic top view of thedisk drive apparatus, and FIG. 1B is a cross-sectional view taken alongthe X-X line in FIG. 1A;

[0019]FIGS. 2A and 2B are enlarged, cross-sectional views of animportant portion of the first embodiment, showing a condition in whicha clamp member is received in a turntable; FIG. 2A is a view showing astate that the claim member passes the dead point in rotating in a Cdirection, and FIG. 2B is a view showing a receiving state;

[0020]FIGS. 3A and 3B are enlarged, cross-sectional views of animportant portion of the first embodiment, showing a condition in whichthe clamp member is projected to an engaged position; FIG. 3A is a viewshowing a state that the clamp member passes another dead point inrotating in a D direction, and FIG. 3B is a view finishing theprojection;

[0021]FIG. 4 is a cross-sectional view showing a condition in which adisk is placed on the disk drive apparatus;

[0022]FIG. 5 is a cross-sectional view showing a condition in which thedisk drive apparatus attaches the disk;

[0023]FIG. 6 is a cross-sectional view showing a condition in which thedisk drive apparatus of FIG. 1 clamps a thin disk;

[0024]FIG. 7 is a cross-sectional view showing a condition in which thedisk drive apparatus of FIG. 1 clamps a thick disk;

[0025]FIG. 8A is a cross-sectional view showing a clamp mechanismportion of the disk drive apparatus of FIG. 1 and FIG. 8B is an enlargedcross-section view of an important portion of L in FIG. 8A;

[0026]FIG. 9 is a view showing a condition in which a disk, contained ina cartridge, is attached to the disk drive apparatus of FIG. 1;

[0027]FIG. 10 is a cross-sectional view of a second embodiment of a diskdrive apparatus according to the invention;

[0028]FIG. 11 is an enlarged, cross-sectional view showing a voice coilmotor portion of FIG. 10;

[0029]FIGS. 12A and 12B are views explanatory of the magnetization of alinear magnet of the second embodiment, FIG. 12A being a viewillustrating its principle, and FIG. 12B being a schematic view showingthe actual magnetizing operation;

[0030]FIG. 13 is a view showing a forcible discharge position of thedisk in the second embodiment; and

[0031]FIGS. 14A and 14B are views showing the case where the disk isplaced off-center on the turntable in the first embodiment, FIG. 14Abeing a plan view, and FIG. 14B being a vertical cross-sectional view.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Preferred embodiments of the present invention will now bedescribed with reference to the drawings.

[0033] First Embodiment

[0034]FIGS. 1A and 1B are views of a first embodiment of a disk driveapparatus according to the invention, showing a condition before a diskloading operation is effected. FIG. 1A is a schematic top view of thedisk drive apparatus, and FIG. 1B is a cross-sectional view taken alongthe X-X line in FIG. 1A. In FIGS. 1A and 1B, the disk drive apparatus ofthe first embodiment includes a spindle motor 3 for rotating a disk 1 ona turntable (rotary support means) 22. A shaft 11 is mounted at acentral portion of the spindle motor 3. The shaft 11 rotates at highspeed, and therefore is made of a material (e.g. stainless steel (JISSUS420J2) or the like) having high hardness and high surface precision.A bearing 12 is mounted around the outer periphery of the shaft 11. Theshaft 11 is rotatably borne or supported by the bearing 12, with aclearance of several microns formed therebetween. Generally, in view ofthe cost, this bearing 12 is made of sintered metal, and particularlywhen the high performance is required, a ball bearing is used as thebearing 12. A bearing housing 13 is provided around the outer peripheryof the bearing 12. The bearing 12 is press-fitted into the bearinghousing 13. Generally, the bearing housing 13 is made of BsBM (brass),but in the present invention, the bearing housing 13 is made of ordinaryferromagnetic metal (free-cutting steel in this embodiment). A thrustbearing 14 bears a thrust load of the shaft 11. The thrust bearing 14 ismade of a resin (e.g. Polyphenylene sulfide (hereinafter referred byPPS), or metal having high strength and good sliding properties. Thethrust bearing 14 is mounted on the bearing housing 13. The bearinghousing 13 is fixedly secured to a base 15. The base 15 is made, forexample, of a ferromagnetic material such as SECE (JIS-G3313;Electrolytic zinc-coated steel sheets, hereinafter referred by SECE).

[0035] A plunger (reciprocally-moving means) 16, having the function ofpivotally moving clamp members 21, is provided around the outerperiphery of the bearing housing 13 so as to reciprocally move in adirection of the axis of the shaft 11. The plunger 16 is formed into acylindrical shape having a flange 17. The plunger 16 is made of ordinaryferromagnetic metal (e.g. free-cutting steel). The flange 17 is formedat that end of the plunger 16 directed toward a disk-placing surface(that is, in a direction of arrow A), and extends radially outwardlytherefrom. A bobbin 18, made of a resin, is provided around the outerperiphery of the plunger 16. The bobbin 18 includes a cylindrical bodyhaving flanges formed respectively at opposite ends thereof. A copperwire is wound on an outer peripheral surface of the cylindrical bodybetween the flanges to form a coil 19. The coil 19 serves as magnetizingmeans or exciting means. In order to enhance the space factor, a squareshaped copper wire is used as this copper wire. A plunger spring(compression coil spring) 20 acts between the bobbin 18 and the plunger16. Therefore, the plunger 16 is urged in the direction of arrow A bythe plunger spring 20.

[0036] The turntable 22 is mounted coaxially on the shaft 11 at aposition adjacent to the flange 17 of the plunger 16. This turntable 22is formed by precisely machining free-cutting steel (whose surface isplated) using a NC (Numerically controlled) lathe or the like (itsroundness is precise on the order of about 10 microns), and theturntable 22 is rotated by the shaft 11. A center hub 23 is formed in aprojected manner at a central portion of the turntable 22, and itsprojected surface is a tapered slant. The center hub 23 can be fittedinto a clamp hole 2, formed through the central portion of the disk 1,so as to bring the center of the disk 1 into agreement with the axis ofthe shaft 11. The amount of projecting of the center hub 23 is not morethan the thickness of the disk 1 placed on the turntable 22. In thepresent invention, the disk 1 is positioned on the turntable 22 by theclamp members 21 (more fully described later), and therefore theconfiguration of the center hub is not an essential feature of thepresent invention.

[0037] The plurality of clamp members 21 are pivotally mounted on theinner peripheral portion of the turntable 22. These clamp members 21,serving as pivotal attaching means, can be retainingly engaged with theedge of the clamp hole 2 in the disk 1 to fix the disk 1. The clampmember 21 includes a claw portion for engaging with the clamp hole 2,and a cam surface portion in contact with a press plate 28 (describedlater). As shown in FIG. 1A, the three clamp members 21 are mounted onthe turntable 22, and are spaced at equal intervals circumferentiallyaround the shaft 11. With the use of the three clamp members 21, theclamp hole (center hole) 2 can be aligned with the shaft 11. Of curse,the number of the clamp members 21 is not limited to three, but asuitable number of (for example, 4 or 6) clamp members 21 can be useddepending on the diameter of the central hole 2 and the press fixingforce. The press plate 28 is in the form of an annular, flat plate, andis mounted on the inner peripheral surface of the turntable 22 so as toreciprocally move upward and downward (FIG. 1B). The press plate 28 isheld in contact with the cam surface portions of the clamp members 21,and this press plate 28 is urged in the direction of arrow A (FIG. 1B)by a clamp spring (compression coil spring) 29. As shown in FIGS. 1B and2, the clamp spring 29 extends between the press plate 28 and a pocketportion (recess) formed on a lower portion of the inner peripheralsurface of the turntable 22.

[0038] As shown in FIGS. 2A and 3A, the cam surface portion of the clampmember 21 has two dead points (which means points of contact of the camsurface portion 21 a with the press plate 28, and an operating line,extending from each of these contact points in the direction of urgingof the press plate 28, passes through the axis 21 c of pivotal movement.An angular moment to the clamp member 21 will not be generated at thesecontact points.) corresponding to the angle of pivotal movement (angularmovement). When the clamp member 21 is pressed or pushed beyond one deadpoint 21 d by the press plate 28, as shown in FIG. 3A, the clamp member21 is pivotally moved in a direction to engage with the clamp hole 2,and when the clamp member 21 is pressed beyond the other dead point 21 bby the press plate 28, as shown in FIG. 2A, the clamp member 21 ispivotally moved in a direction away from the clamp hole 2, and isreceived in the turntable 22. Namely, urging means, comprising the pressplate 28 and the clamp spring 29, assists the plunger 16 in pivotallymoving the clamp members 21, and assists the clamp members 21 in beingkept in the engaged position and the received position.

[0039] The function of the cam surface portion will be described infurther detail. FIG. 2B is an enlarged, cross-sectional view of animportant portion, showing a condition in which each clamp member isreceived in the turntable 22. In FIG. 2B, the cam surface portion 21 aof the clamp member 21 is held in contact with a flat surface portion 28x of the press plate 28. The press plate 28 is always urged upwardly bythe clamp spring 29, and the flat surface portion 28 x is disposedradially outwardly of the axis 21 c of pivotal movement, and thereforethe clamp member 21 is always subjected to a pivotally-moving force in adirection D. Therefore, even if the clamp member 21 is subjected toslight disturbance such as vibration, the clamp member 21 can be kept inthe received condition.

[0040]FIG. 3B is an enlarged, cross-sectional view of an importantportion, showing a condition in which each clamp member is projected tothe engaged position. In FIG. 3B, the clamp member 21 holds the disk 1.The cam surface portion 21 a of the clamp member 21 is held in contactwith a slanting surface 28 y of the press plate 28. The press plate 28is always urged upwardly by the clamp spring 29, and the point ofcontact of the clamp member 21 with the slanting surface 28 y isdisposed radially inwardly of the axis 21 c of pivotal movement, andtherefore the clamp member 21 is always subjected to a pivotally-movingforce in a direction of C. Therefore, the clamp member 21 can be alwayskept in the engaged condition.

[0041] The pivotal movement mechanism, described above in detail,produces the following remarkable effects. Namely, the plunger 16 needonly to apply a pressing-up force and a pressing-down force to the clampmembers 21 only during the time when the cam surface of each clampmember 21 rotates between the two dead points thereon. Thus, the plunger16 need only to trigger the position change of the clamp members 21.Therefore, the plunger 16 need only to be energized for the time periodnecessary for this triggering operation, and the energy can be savedgreatly.

[0042] Referring again to FIG. 1B, the spindle motor 3 is provided atthe outer peripheral portion of the turn-table 22 at the reverse surfacethereof facing away from the disk-placing surface. The spindle motor 3has a construction of an axial gap-type DC brushless motor. A rotormagnet 24 is mounted on the outer peripheral portion of the turntable22. This rotor magnet 24 has a thickness of about 0.5 mm to about 2 mm,and is divided into a plurality of (for example, 8 or 12) N/S poles. Aboard 25 is provided, and is spaced at a predetermined distance from therotor magnet 24. A plurality of printed coils, laminated by etching, areformed on the board 25, and function as armature coils (stator coils).In order to achieve a thin design of the motor, the thickness of thisboard 25 is not more than 1 mm. Further, a lower rotor 26 is provided,and is spaced at a predetermined distance from the board 25. The lowerrotor 26 is made of a ferromagnetic material, and the armature coils onthe board 25 are interposed between the rotor magnet 24 and the lowerrotor 26, and with this construction an electromagnetic drive force canbe produced in the spindle motor 3.

[0043] Thus, the turntable 22 is formed integrally with the rotor magnet24 of the motor constituting a magnetic circuit, and with thisconstruction, the thin design of the device is achieved, and also thenumber of the component parts is reduced.

[0044] The disk attaching operation, effected by the above plunger 16and the above clamp members 21, will now be described. When the coil 19is excited by exciting current, an electromagnetic force is produced inthe direction of an axial thrust of the shaft 11, and the plunger 16 ofa magnetic material is attracted by this electromagnetic force, and ismoved toward the base 15 (in a direction of arrow B) in parallel to theaxis of rotation of the shaft 11. At an initial stage of the movement,the clamp members 21 are pivotally moved in the direction of arrow D bythe flange 17. Namely, the cam surface portion of each clamp member 21is pressed down in the direction of arrow B, so that the clamp member 21is pivotally moved in the direction of arrow D. When each clamp member21 is pivotally moved beyond the dead point 21 b of the cam surfaceportion, as shown in FIG. 2A, the clamp member 21 is pressed by thepress plate 28, and is further pivotally moved in the direction D, andis received in the turntable 22. In this condition, the disk 1 can bedetached or disengaged from the turntable 22.

[0045] On the other hand, when the coil 19 is no-exciting condition, theplunger 16 is urged by the plunger spring 20 to be moved in thedirection of arrow A, as shown in FIGS. 1B and 3A. The clamp members 21are pivotally moved in the direction of arrow C by the flange 17. Morespecifically, at an initial stage of the movement, the claws of theclamp members 21 are pushed up in the direction of arrow A, and theclamp members 21 are pivotally moved in the direction of arrow C. Wheneach clamp member 21 is pivotally moved beyond the dead point 21 d ofthe cam surface portion, the clamp member 21 is pressed by the pressplate 28, and is further pivotally moved in the direction C, so that theclamp members 21 are projected from the turntable 22 to be retaininglyengaged in the clamp hole 2 in the disk 1, thereby fixing the disk 1.

[0046] Thus, in the disk drive apparatus of the first embodiment, whenthe disk 1 is to be attached to and detached from the turntable 22,there is no part or member which projects from the turntable 22. As aresult, there can be obtained the disk drive apparatus which is reducedin thickness in the direction of the axis of the shaft 11.

[0047] The plunger 16 is arranged in concentric, coaxial relation to theshaft 11, and can slide on the outer peripheral surface of the bearinghousing 13 in the direction of the axis of the shaft 11. Therefore, themotor and the solenoid can have common constituent parts, and by doingso, the clamp mechanism can be formed into a compact design. Andbesides, since the plunger 16, the bobbin 18 and the coil 19, which arethe constituent parts of the solenoid, are provided around the shaft 11,the clamp mechanism can be formed into the thin, compact design.Furthermore, when the plunger 16 is moved, the plunger 16 abuts againstthe base 15, and thus the base 15 serves as a stopper. In this respect,also, the motor and the solenoid have the common constituent part, andtherefore the thin and compact design of the clamp mechanism can beachieved.

[0048] The operation of the disk drive apparatus, employing the clampmechanism of the above construction, will be described. FIG. 4 is across-sectional view showing a condition in which the disk is placed onthe disk drive apparatus. First, in FIG. 1B, (1) the user holds the disk1 with his fingers, and puts this disk 1 into a disk insertion hole. Asa result, this disk 1 is introduced into the disk drive apparatus fromone side of the turntable 22 (that is, from the right side as indicatedby arrow X in FIG. 1B). (2) Then, when about a half of the disk 1 isinserted, with its central hole introduced into the disk driveapparatus, this disk 1 is transferred to the turntable 22 by transfermeans (e.g. a belt conveyor which is no matter of the present invention,and therefore explanation and illustration thereof will be omittedhere), and is placed on the center hub 23. FIG. 4 shows the disk in thiscondition. During the above periods (1) and (2), the coil 19 is excitedby exciting current, so that the clamp members 21 are received in theturntable 22. (3) Then, when the disk is thus placed on the turntable,the exciting current in the coil 19 is cut-off. As a result, the plunger16 moves upward, so that the clamp members 21 are pivotally moved in thedirection C, and are projected from the turntable 22, as describedbefore. (4) The clamp members 21 are further pivotally moved in thedirection C under the pressing force of the clamp spring 29 to beprojected from the turntable 22, and are retainingly engaged with edgeof the clamp hole 2 in the disk 1, thereby fixing the disk 1. Theclamping force, produced by the clamp members 21 at this time, can beadjusted by adjusting the spring force of the clamp spring 29. FIG. 5 isa cross-sectional view showing a condition in which the disk driveapparatus fixes the disk in FIG. 1B. In this manner, the fixing of thedisk 1 is finished.

[0049] In FIG. 5, the disk 1 has a thickness of 1.2 mm which is thethickness of a standard disk. However, there are occasions when anoff-specification disk is used. For example, FIG. 6 shows a condition inwhich a thin disk (having a thickness of about 1 mm) is clamped, andFIG. 7 shows a condition in which a thick disk (having a thickness ofabout 1.7 mm) is clamped. As shown in FIGS. 6 and 7, the clamp members21 fix the clamp hole 2 under the spring force of the clamp spring 29,and therefore even if disks of difference thicknesses (for example, inthe range of about from 1 mm to 1.7 mm) are used, these disks can bepositively fixed by the clamp members 21.

[0050] And besides, in the disk drive apparatus of the presentinvention, the clamp members are fixedly engaged with the edge of theclamp hole 2, and therefore even if disks have different outer diameters(for example, 8 cm and 12 cm), these disks can be positively fixed.Furthermore, even a disk whose outer shape is not circular can bepositively fixed.

[0051] The spindle motor 3 and the disk clamp mechanism are integrallyformed with each other in a concentric manner, and the thickness of thisintegral construction (from the outer surface of the base 15 to thedistal end of each clamp member 21 in the clamped condition) is equal toor less (not more) than 11.5 mm. With this construction, the overallthickness of the disk drive apparatus, including the space used fortransferring the disk 1, can be made not more than 12.7 mm. As a result,the disk drive apparatus can be mounted even on a note book-typecomputer required to have a compact, thin design, and the disk driveapparatus of high convenience can be provided to the operator.

[0052] In the first embodiment, the disk is released upon energizationwhereas the disk is held or retained upon de-energization. Referring tothis reason, when the disk is attached, power consumption for thedriving of the spindle motor 3 increases, and therefore the coil 19 isenergized when the disk is released, and by doing so, the powerconsumption can be leveled. However, the clamp mechanism of the presentinvention is not limited to such a mode of use, but the disk can be heldupon energization, and can be released upon de-energization by suitablyapplying the plunger 16, the polarity of the coil 19, the plunger spring20 and the clamp spring 29 to other combination. Such a modification canbe derived from the present invention, and will be readily appreciated,and therefore explanation thereof will be omitted.

[0053] Using the following constructions in addition to the constructiondescribed above in detail, the advantages and conveniences are furtherenhanced. One example thereof is shown in FIGS. 8A and 8B. FIG. 8A is across-sectional view showing the clamp mechanism of the disk driveapparatus of FIG. 1B and FIG. 8B is an enlarged view of an importantportion of L in FIG. 8A. In these Figures, a projection 21 e is formedon the clamp member 21. The projection 21 e is formed on that portion ofthe clamp member 21 which can abut against the edge of the clamp hole 2.

[0054] The clamp member 21 is pivotally moved by the triggeringoperation of the plunger 16, and abuts against the edge of the clamphole 2. At this time, a rotating stress (torque), acting obliquelydownwardly, is always applied to the peripheral edge of the clamp hole 2from the upper side by the claw of each clamp member 21. Therefore, byforming the projection 21 e on each clamp member 21, forces, appliedrespectively from the projections 21 e of the clamp members 21, insteadof such rotating stresses, can bring the clamp hole 2 into agreementwith the center. Thus, the centering of the disk 1 can be easilyeffected.

[0055] Another example will be described. FIG. 9 is a view showing acondition in which a disk, contained in a cartridge, is attached to thedisk drive apparatus of FIG. 1. Examples of disk mediums include thekind (e.g. a MD, a PD and a DVD-RAM) in which a disk is contained in acartridge 27. In the disk drive apparatus of the present invention,there is no portion or part which projects from the turntable 22 to thedisk-attaching surface, as described above. And besides, the pivotalmovement mechanism of the clamp member 21 is received in the turntable22. Therefore, not only the bare disk 1 but also the disk 1, containedin the cartridge 27, can be easily attached to and detached from theturntable.

[0056] As described above, in the present invention, the fixing andrelease of the disk 1 can be controlled by non-exciting and exciting thecoil 19, and therefore there can be provided the disk drive apparatuscapable of automatic attachment of the disk 1. And besides, the firstembodiment can provide the disk drive apparatus which is the solenoidtype having the movable plunger 16, and in which the number of thecomponent parts is reduced, thus providing the compact and sturdy designof the disk drive apparatus.

[0057] Second Embodiment

[0058] In a second embodiment, instead of the solenoid type, a voicecoil motor (VCM), employed in a linear motor and so on, is used asreciprocally-moving means. The second embodiment will now be describedwith reference to the drawings. FIG. 10 is a cross-sectional view of adisk drive apparatus according to the second embodiment of the presentinvention, and FIG. 11A is an enlarged, cross-sectional view of a voicecoil motor portion of FIG. 10. In FIGS. 10 and 11A, reference numeral 3denotes a spindle motor, reference numeral 11 a shaft, reference numeral12 a bearing, reference numeral 13 a bearing housing, reference numeral14 a thrust bearing, reference numeral 15 a base, reference numeral 19 acoil, reference numeral 21 a clamp member, reference numeral 22 aturntable, reference numeral 23 a center hub, reference numeral 24 arotor magnet, reference numeral 25 a board, reference numeral 26 a lowerrotor, reference numeral 28 a press plate, and reference numeral 29 aclamp spring. These constituent parts are similar in configuration andmaterial to those described above for the first embodiment, andtherefore explanation thereof will be omitted here.

[0059] The main difference of the second embodiment from the firstembodiment resides in the construction of the voice coil motor. A slider31 can slide on an outer peripheral surface of the bearing housing 13 ina direction of the axis of the shaft 11. The slider 31 is made of amaterial (e.g. aluminum) which is lightweight, and has rigidity to acertain degree. A slider spring 30 acts between the bearing housing 13and the slider 31 to urge the slider 31 toward a disk-placing surface(that is, in a direction of arrow A in FIG. 11A) as in the firstembodiment. The slider spring 30 is a compression coil spring formed bywinding a wire element into a generally conical shape. When the sliderspring 30 is fully compressed, the turns of the coil wire do not overlapeach other for the slider 31 reaching its bottom position (see FIG.11A). A stopper 32 limits the upward movement of the slider 31. Thestopper 32 also prevents the slider 31 from contacting the clamp members21 when the disk 1 is chucked. A linear magnet 33 is made of aferromagnetic material, and is formed into a cylindrical shape. Thosesurface of the linear magnet 33, disposed perpendicular to the axis ofthe shaft 11 (that is, disposed radially of the spindle motor 3), aremagnetized to have magnetic poles. The slider 31 is provided around theouter periphery of the bearing housing 13, and the linear magnet 33 isprovided around the outer periphery of the slider 31, and these aremounted coaxially with the shaft 11. A back yoke 34 has the function ofefficiently producing a magnetic flux between the bearing-housing 13 andthe linear magnet 33. With the above construction, when the coil 19 isexcited, coil current flows across the magnetic flux, so that the slider31 is moved upward and downward along the outer peripheral surface ofthe bearing housing 13.

[0060] In the second embodiment of the present invention having theabove construction, the slider 31 moves together with the coil 19, andtherefore the moving coil-type is provided. Except the moving coil-type,the operation from the placing of the disk 1 on the turntable 22 to thecompletion of the fixing of the disk by the clamp member 21 is similarto that described above for the first embodiment. Therefore, descriptionof the operation of the second embodiment will be omitted here. In thesolenoid type of the first embodiment, the electromagnetic force variesin accordance with the position of the plunger 16. On the other hand, inthe moving coil-type, the drive force is determined by the electriccurrent and the magnetic flux, and therefore the clamp members 21 can besmoothly operated by controlling the coil current.

[0061] Next, the magnetization of the linear magnet 33 will bedescribed. FIGS. 12A and 12B are views explanatory of the magnetizationof the linear magnet. The linear magnet 33 has a cylindrical shape asshown in FIG. 11A. The principle of magnetization is well known, and amaterial, having a high coercive force, is placed in a magnetic field soas to be magnetized. Therefore, for magnetizing a cylindrical member, itis necessary to provide magnetic poles of the same polarity in opposedrelation to each other as shown in FIG. 12A (which shows the principle),and in this case it is difficult to obtain the uniform magnetization(and hence the uniform magnetic flux). Therefore, the linear magnet 33is circumferentially divided into four sections, and each of the foursections is magnetized in a uniform magnetic field, as shown in FIG.12B. These four sections are combined together into a cylindrical shapeto thereby provide the linear magnet 33 which produces a uniform, highmagnetic flux.

[0062]FIG. 11B shows a modified construction, and in contrast with theconstruction of FIG. 11A, a coil 19 and a bobbin are fixed, and a slider31′ is fixed to a linear magnet 33′, and the linear magnet 33′ isreciprocally movable, thus providing the moving magnet-type. In thisconstruction, the operation and the magnetization of the linear magnet33′ are similar to those described above for the moving coil-type, andtherefore explanation thereof will be omitted here.

[0063] Next, the operation of the clamp members 21, effected whenforcibly discharging the disk 1, will be described. Let's assume thatpower failure occurs when the disk 1 is held in the fixed condition inthe disk drive apparatus of the first or the second embodiment. In thiscase, the operator mechanically discharges the disk 1 in a forciblemanner. Therefore, by the forcible discharge operation (usually effectedby an eject button (not shown)), the disk 1 is lifted from the engagedposition (shown in FIG. 5 or FIG. 10) to a path (shown in FIG. 13) forthe forcible discharge. FIG. 13 shows the forcible discharge position.At this time, each clamp member 21 is disposed at the dead pointposition as described before in connection with the operation of theclamp member 21, and therefore the clamp member 21 remains at the deadpoint position, and also the disk 1 remains at the forcible dischargeposition.

[0064] Then, when the disk 1 is moved in a discharge direction bycontinuing the forcible discharge operation, one or two of the threeclamp members 21 are pressed against the inner peripheral edge of thedisk 1. As a result, the thus pressed clamp member(s) 21 is pivotallymoved in the direction toward the received position. When the disk 1continues to move, the cam surface portion 21 a is angularly movedbeyond the dead point. Further, the clamp member 21 is pressed to bepivotally moved, so that the rear surface of the clamp member pressesdown the plunger 16 or the slider 31. As a result, the other one or twoclamp members 21 are pushed at their cam surface 21 a by the plunger 16or the slider 31, and begin to be pivotally move. Finally, the camsurface portion 21 a is angularly moved beyond the other dead point, andthe plunger spring 20, the slider spring and the clamp spring 29 are sobalanced with one another that the clamp members 21 are held in theirrespective received positions. Thus, all of the clamp members 21 arereceived in the turntable 22, thereby enabling the discharge of the disk1.

[0065] Let's consider another abnormal condition. As described above inFIG. 4, the disk 1 is placed on the center hub 23. However, when thedisk 1 is placed on the center hub 23, the disk 1 is not always centered(that is, not aligned with the center hub 23), which is caused byvarious errors. FIG. 14 is a view showing a condition in which the diskis placed off-center on the center hub.

[0066] However, as described above in detail for the operation of theclamp member 21, when each clamp member 21 is to fix the disk 1, thedistal end of the clamp member 21 moves along a path extending from theinner peripheral side to the outer peripheral side of the turntable 22.Therefore, even if the disk 1 is disposed off-center, the clamp members21 can fix the disk 1 while correcting the position of the disk 1. Forthe same reason, even if the inner diameter of the hole in the disk, aswell as its thickness, is changed, the clamp members 21 can fix the disk1 while correcting the position of the disk. Namely, any particularprecision is not required for the mechanism for transferring the diskfrom the insertion hole to the turntable. Therefore, the transfermechanism can have a simple and inexpensive construction, and the diskdrive apparatus can be produced at lower costs.

[0067] As in the first and second embodiments, the spindle motor and thedisk clamp mechanism are integrally formed with each other in aconcentric manner, and its thickness T1 (from the outer surface of thebase 15 to the distal end of each clamp member 21 in the clampedcondition) (see FIG. 10) is not more than 11.5 mm. With thisconstruction, the overall thickness T2 of the disk drive apparatus,including the space used for transferring the disk 1, can be made notmore than 12.7 mm. As a result, the disk drive apparatus can be mountedeven on a note book-type computer required to have a compact, thindesign, and the disk drive apparatus of high convenience can be providedto the operator.

[0068] The voice coil motor of the above construction, serving as thereciprocally-moving means, can use the bearing housing 13 as part of themagnetic circuit instead of the back yoke. Therefore, the thinner andmore compact design of the clamp mechanism can be achieved.

[0069] In addition to the features of the first embodiment, the secondembodiment of the above construction has the feature that the elementsof the reciprocally-moving mechanism can be made of a relativelylightweight material, so that the reciprocal movement can be achieved byless electromagnetic energy.

[0070] As described above in detail, in the present invention, there isprovided the disk drive apparatus suited for a compact and lightweightdesign and a thin design, and there are provided the medium attachingdevice and the disk drive apparatus in which the automatic attachment ofthe disk can be effected without the need for the attaching operation bythe operator.

What is claimed is:
 1. A medium attaching device comprising rotarysupport means for holding a disk medium thereon, and rotation drivemeans for rotating said rotary support means so as to rotate said diskmedium; wherein said rotation drive means includes reciprocally-movingmeans for reciprocal movement in a direction of an axis of a rotationshaft; wherein said rotary support means has a plurality of pivotalattaching means pivotally mounted thereon, and each of said pivotalattaching means is pivotally movable between a fixed position where saidpivotal attaching means fixedly holds said medium and a receivedposition where said pivotal attaching means is received in said rotarysupport means, and said plurality of pivotal attaching means areprovided on said rotary support means in concentric relation to the axisof said rotation shaft; and wherein said pivotal attaching means areengaged with said reciprocally-moving means, and are pivotally moved bythe reciprocal movement of said reciprocally-moving means, therebyfixing and releasing said recording medium relative to said rotarysupport means.
 2. A disk drive apparatus for holding and rotating a diskmedium, comprising a medium attaching device as defined in claim 1 . 3.A medium attaching device comprising rotary support means for holding adisk medium thereon, and rotation drive means for rotating said rotarysupport means so as to rotate said disk medium; wherein said rotationdrive means includes reciprocally-moving means, which is mounted aroundan outer periphery of a rotation shaft in coaxial relation thereto so asto reciprocally move in a direction of an axis of said rotation shaft,and exciting means wound around the outer periphery of said rotationshaft; wherein said rotary support means has a plurality of pivotalattaching means pivotally mounted thereon, and each of said pivotalattaching means is pivotally movable between a fixed position where saidpivotal attaching means fixedly holds said recording medium and areceived position where said pivotal attaching means is received in saidrotary support means, and said plurality of pivotal attaching means areprovided on said rotary support means in concentric relation to the axisof said rotation shaft; and wherein said pivotal attaching means areengaged with said reciprocally-moving means, and are pivotally moved bythe reciprocal movement of said reciprocally-moving means, therebyfixing and releasing said recording medium relative to said rotarysupport means.
 4. A medium attaching device according to claim 3 , inwhich said reciprocally-moving means is made of a ferromagneticmaterial, and is reciprocally moved by a magnetic attraction forceproduced by said exciting means.
 5. A medium attaching device accordingto claim 3 , in which said reciprocally-moving means is constructedintegrally with said exciting means, and a perpendicular magnetic bodymade of a ferromagnetic material and formed in a generally cylindricalshape, which is magnetized perpendicularly to the axis of said rotationshaft, is disposed around an outer periphery of said reciprocally-movingmeans in coaxial relation to said rotation shaft.
 6. A medium attachingdevice according to claim 3 , in which said reciprocally-moving means ismade of a ferromagnetic material, and is formed into a perpendicularmagnetic body of a generally cylindrical shape which is magnetizedperpendicularly to the axis of said rotation shaft, and said excitingmeans is wound on the outer periphery of said reciprocally-moving meansin coaxial relation to said rotation shaft.
 7. A disk drive apparatusfor holding and rotating a disk medium so as to reproduce information,comprising a medium attaching device as defined in claim 3 .
 8. A mediumattaching device according to claim 3 , in which a thickness of saidmedium attaching device in a plane, including the axis of said rotationshaft, is equal to or less than 11.5 mm.
 9. A disk drive apparatus forholding and rotating a disk medium so as to reproduce information,comprising a medium attaching device as defined in claim 8 .
 10. A diskdrive apparatus according to claim 9 , in which an overall thickness ofsaid disk drive apparatus is equal to or less than 12.7 mm.
 11. A mediumattaching device comprising rotary support means for holding a diskmedium thereon, and rotation drive means for rotating said rotarysupport means so as to rotate said disk medium; wherein said rotationdrive means includes reciprocally-moving means, which is mounted aroundan outer periphery of a rotation shaft in coaxial relation thereto so asto reciprocally move in a direction of an axis of said rotation shaft,and exciting means wound around the outer periphery of said rotationshaft; wherein said rotary support means has a plurality of pivotalattaching means pivotally mounted thereon, and each of said pivotalattaching means is pivotally movable between a fixed position where saidpivotal attaching means fixedly holds said disk medium and a receivedposition where said pivotal attaching means is received in said rotarysupport means, and said plurality of pivotal attaching means areprovided on said rotary support means in concentric relation to the axisof said rotation shaft; wherein there is provided urging means whichassists said pivotal attaching means in being pivotally moved, and urgessaid pivotal attaching means so that said pivotal attaching means canremain at said fixed position and said received position; wherein eachof said pivotal attaching means has a claw for retaining said diskmedium, and a cam surface portion which receives an urging force of saidurging means; and wherein said pivotal attaching means are engaged withsaid reciprocally-moving means, and are pivotally moved by thereciprocal movement of said reciprocally-moving means, thereby fixingand releasing said recording medium relative to said rotary supportmeans.
 12. A medium attaching device according to claim 11 , in whichsaid claw has a projection for abutment against an inner surface of acentral hole in said disk medium, and said cam surface portion has afirst dead point, which initiates the pivotal movement of said pivotalattaching means toward said fixed position upon reception of the urgingforce of said urging means, and a second dead point which initiates thepivotal movement of said pivotal attaching means toward said receivedposition upon reception of the urging force of said urging means.
 13. Amedium attaching device according to claim 11 , in which saidreciprocally-moving means is made of a ferromagnetic material, and isreciprocally moved by a magnetic attraction force produced by saidexciting means.
 14. A medium attaching device according to claim 11 , inwhich said reciprocally-moving means is constructed integrally with saidexciting means, and is formed into a perpendicular magnetic body made ofa ferromagnetic material and formed in a generally cylindrical shape,which is magnetized perpendicularly to the axis of said rotation shaft,is disposed about an outer periphery of said reciprocally-moving meansin coaxial relation to said rotation shaft.
 15. A medium attachingdevice according to claim 11 , in which said reciprocally-moving meanscomprises a perpendicular magnetic body made of a ferromagnetic materialand formed in a generally cylindrical shape, which is magnetizedperpendicularly to the axis of said rotation shaft, and said excitingmeans is wound on the outer periphery of said reciprocally-moving meansin coaxial relation to said rotation shaft.
 16. A disk drive apparatusfor holding and rotating a disk medium so as to reproduce information,comprising a medium attaching device as defined in claim 11 .
 17. Amedium attaching device according to claim 11 , in which a thickness ofsaid medium attaching device in a plane, including the axis of saidrotation shaft, is equal to or less than 11.5 mm.
 18. A disk driveapparatus for holding and rotating a disk medium so as to reproduceinformation, comprising a medium attaching device as defined in claim
 17. 19. A disk drive apparatus according to claim 18 , in which an overallthickness of said disk drive apparatus is equal to or less than 12.7 mm.